I found a DMG of 1.5.11b2 which is what I think I was using before I got my laptop with Yosemite. If you happen to read this a few months on, I found you can download it from cachefly by intelligently guessing the URL based off the pattern from the 1.5.10.3b1 release:https://adiumx.cachefly.net/Adium_1.5.11b2.dmg

If that doesn't work, I can provide a download link to the copy I have.

If there's anything I can help with to keep the backend chugging, please let me know. I'm not much of a developer, but I'm a helluva web debugger

Someone on Viennas Github mentioned not receiving any confirmation email when creating an account here on Cocoaforge. Is there an issue with that at the moment?

He wrote this:

Hi, I did register recently at the cocoaforge forums to ask this, but wasn't getting the confirmation email. Today I checked and there seem to be problems with cocoaforge, the main domain points at some goddady iframe (hopefully I didn't break anything during registration).